The Redline MT-90 which a few of us run is supposed to be good for the materials in the toyota trannys. There's lots of stuff online about it... Check it out. It makes the tranny shift "crisper" too. I think the syncros grab a little better with it.

Meh, I ran it and my tranny didn't seem to care that it cost 5 times as much compared to Castrol GL-4 that it replaced. Problem is Hypoy-C went to GL-5 and I can't find the GL-4 version anymore.

It should be noted that the reason ZDDP has been reduced or eliminated in motor oil is it ruins catalytic converters (the film is flashed off the cylinder walls during combustion). That is the reason the API cannot certify Amsoil, too much ZDDP. Whether or not it matters, I dunno. I would prefer the EP features but it's also something of an urban legend that it's really needed anymore.

Cam blanks for 20 years now have been made of hardened steel and machined, so there is no mild steel to wear like years ago. The original Internet hubbub was a Hot Rod or something magazine article that suggested that the lack of ZDDP was why reground cams wore out faster. The truth is probably that in the 1960s and 1970s machine tools were not as good and so they made cam blanks from mild steel, machined them and then hardened them, so during break-in you were case hardening the surfaces.

Now the components are much better and there's less of that needed during break-in. That's part of the reason manufacturers now don't have nearly as complex of initial operating requirements on new cars. Anyway, when they used to regrind cams they would take off the case hardened face and with the lack of zinc the new cam would never harden properly. But it matters a whole lot less if the cam is made from hardened steel from the get-go.

So as catalytic converters started showing up in the 1970s and 1980s the API had to reduce the ZDDP requirements so that they would not ruin them. But lots of people still had their old 1960s and 1970s pre-cat engines that they were rebuilding. The available oil did not work for the old junk with reground original (from 1964) cams. Now very few people are trying to keep their old junk on the road and those of us that do are using new cams which would not be made the same as they did in 1964 and so it's probably not nearly as much of an issue. Still I dumped in zinc break-in additive on my new engine, although I don't worry too much about it for the regular oil.

Just go with the diesel oil, as long as it has a "C" rating it has the higher anti-friction additives. All of the top line diesel oils that are rated for the new diesels have to be low ash so they don't contaminate the DPF's and they will be CJ rated.